The present invention relates to a seal structure for relatively rotational members to be employed between a rotary member, such as a coupling exposed to and connected to a propeller shaft of a four-wheel drive vehicle, and a stationary member that retains the rotary member to a vehicle body.
In general, attempts have heretofore been made to propose structures as disclosed in Japanese Patent Application Laid-open No. 1-182633 and 10-292827 wherein a coupling (rotary member) is exposed to and connected to a propeller shaft of a four-wheel drive vehicle and wherein a rotary member is exposed outside and located in the vicinity of a stationary member. With the structure wherein the rotary member is exposed outside and located, as shown in Japanese Patent Application Laid-open No. 10-292827, an attempt has been made to dispose a seal structure, such as a dust cover or seal members, between the rotary member and the stationary member to prevent foreign material from entering a relatively rotational region between the stationary member and the rotary member.